1. Field of the Invention
The present invention relates to a seal structure for an electronic equipment, and more particularly to a seal structure to prevent a water droplet from entering into an inner portion of the electronic equipment such as a cellular phone user terminal or the like. Accordingly, the seal structure in accordance with the present invention is preferably utilized as a seal structure for a waterproofed electronic equipment.
2. Description of the Conventional Art
For example, in the cellular phone user terminal, a casing is formed by a combination of a case and a lid which are fitted to each other, and a gasket 31 constructed by an O-ring or the like made of rubber only is interposed between a case 11 and a lid 21 as partly shown in FIG. 11 to prevent a water droplet from entering into an inner portion of the casing (refer to Japanese Unexamined Patent Publication No. 11-54950). Further, since downsizing and thinning of the casing are now demanded, the gasket 31 is required to have a small cross sectional shape and a low hardness in order to make a burden to the casing as small as possible.
However, if the gasket 31 is made to have a small cross sectional shape and a low hardness as mentioned above, a rigidity of the gasket 31 itself is lowered, and a handling performance (a handling and working property) is lowered. Accordingly, an operating efficiency of a user terminal assembling step is deteriorated in addition to an assembling work of the gasket 31.
In order to solve the problem, as shown in FIG. 12, there can be a thought of integrating a resin film 41 with the gasket 31 over a whole periphery in order to enhance a shape retaining property of the rubber only gasket 31. Since the rigidity of the resin film 41 is higher than that of the gasket 31, the gasket 31 is hardly deformed by the integration of the resin film 41, and the shape retaining property of the gasket 31 is enhanced.
However, if the resin film 41 is embedded in a thickness of the gasket 31 as illustrated, at a time of integration of the resin film 41 with the gasket 31 as mentioned above, reaction force of the gasket 31 becomes higher since a rate of the thickness of the resin film 41 to the height dimension of the gasket 31 is comparatively large. Accordingly, much load is applied to the casing due to the reaction force, and there is fear that the casing may be broken.